MicroRNA-532-5p is a prognostic marker and inhibits the aggressive phenotypes of osteosarcoma through targeting CXCL2

MicroRNA-532 as a probable diagnostic and therapeutic marker in cancer patients

The high mortality rate in cancer patients is always one of the main challenges of the health systems globally. Several factors are involved in the high rate of cancer related mortality, including late diagnosis and drug resistance. Cancer is mainly diagnosed in the advanced stages of tumor progression that causes the failure of therapeutic strategies and increases the death rate in these patients. Therefore, assessment of the molecular mechanisms associated with the occurrence of cancer can be effective to introduce early tumor diagnostic markers. MicroRNAs (miRNAs) as the stable non-coding RNAs in the biological body fluids are involved in regulation of cell proliferation, migration, and apoptosis. MiR-532 deregulation has been reported in different tumor types. Therefore, in the present review we discussed the role of miR-532 during tumor growth. It has been shown that miR-532 has mainly a tumor suppressor role through the regulation of transcription factors, chemokines, and signaling pathways such as NF-kB, MAPK, PI3K/AKT, and WNT. In addition to the independent role of miR-532 in regulation of cellular processes, it also functions as a mediator of lncRNAs and circRNAs. Therefore, miR-532 can be considered as a non-invasive diagnostic/prognostic marker as well as a therapeutic target in cancer patients.

The role of CXCL2-mediated crosstalk between tumor cells and macrophages in Fusobacterium nucleatum-promoted oral squamous cell carcinoma progression

Dysbiosis of the oral microbiota is related to chronic inflammation and carcinogenesis. Fusobacterium nucleatum (Fn), a significant component of the oral microbiota, can perturb the immune system and form an inflammatory microenvironment for promoting the occurrence and progression of oral squamous cell carcinoma (OSCC). However, the underlying mechanisms remain elusive. Here, we investigated the impacts of Fn on OSCC cells and the crosstalk between OSCC cells and macrophages. 16 s rDNA sequencing and fluorescence in situ hybridization verified that Fn was notably enriched in clinical OSCC tissues compared to paracancerous tissues. The conditioned medium co-culture model validated that Fn and macrophages exhibited tumor-promoting properties by facilitating OSCC cell proliferation, migration, and invasion. Besides, Fn and OSCC cells can recruit macrophages and facilitate their M2 polarization. This crosstalk between OSCC cells and macrophages was further enhanced by Fn, thereby amplifying this positive feedback loop between them. The production of CXCL2 in response to Fn stimulation was a significant mediator. Suppression of CXCL2 in OSCC cells weakened Fn's promoting effects on OSCC cell proliferation, migration, macrophage recruitment, and M2 polarization. Conversely, knocking down CXCL2 in macrophages reversed the Fn-induced feedback effect of macrophages on the highly invasive phenotype of OSCC cells. Mechanistically, Fn activated the NF-κB pathway in both OSCC cells and macrophages, leading to the upregulation of CXCL2 expression. In addition, the SCC7 subcutaneous tumor-bearing model in C3H mice also substantiated Fn's ability to enhance tumor progression by facilitating cell proliferation, activating NF-κB signaling, up-regulating CXCL2 expression, and inducing M2 macrophage infiltration. However, these effects were reversed by the CXCL2-CXCR2 inhibitor SB225002. In summary, this study suggests that Fn contributes to OSCC progression by promoting tumor cell proliferation, macrophage recruitment, and M2 polarization. Simultaneously, the enhanced CXCL2-mediated crosstalk between OSCC cells and macrophages plays a vital role in the pro-cancer effect of Fn.

Overexpression of miR-532-5p restrains oxidative stress response of chondrocytes in nontraumatic osteonecrosis of the femoral head by inhibiting ABL1

This study is to probe into the meaning of serum miR-532-5p in nontraumatic osteonecrosis of the femoral head (ONFH), and a molecular mechanism of miR-532-5p in the development of nontraumatic ONFH. This study enrolled 96 patients diagnosed with nontraumatic ONFH and 96 patients with femoral neck fracture. The levels of miR-532-5p, ABL1, MMP-3, MMP-13, and cleaved-caspase3 were determined. Radiographic progression was assessed by ARCO staging system. Visual analog scale (VAS) and Harris hip score (HHS) were employed for evaluation of the symptomatic severity of nontraumatic ONFH. Cell viability and apoptosis in chondrocytes isolated from clinical samples were investigated with CCK-8 and flow cytometry. The levels of lactic dehydrogenase (LDH), superoxide dismutase (SOD), and malondialdehyde (MDA), mitochondrial membrane potential (ΔΨm), and reactive oxygen species (ROS) were determined. miR-532-5p was downregulated in tissues and serum of patients with nontraumatic ONFH, negatively related with ARCO staging and VAS, and positively correlated with HHS. Cell apoptosis, LDH, MDA, and ROS strengthened, while cell viability, ΔΨm, and SOD reduced in chondrocytes of nontraumatic ONFH patients. ABL1 was upregulated in cartilage tissues from nontraumatic ONFH patients. miR-532-5p targeted ABL1, and overexpressed miR-532-5p alleviated nontraumatic ONFH-induced oxidative stress damage of chondrocytes by restraining ABL1. miR-532-5p ameliorated oxidative stress injury in nontraumatic ONFH by inhibiting ABL1.

Tumor-associated macrophages mediate gastrointestinal stromal tumor cell metastasis through CXCL2/CXCR2

BACKGROUND

Tumor-associated macrophages (TAMs) are linked with the progression and poor prognosis of multifarious solid tumors, but the regulatory mechanisms involved in gastrointestinal stromal tumors (GIST) remain indistinct. This study intended to delve into the job of TAM-derived chemokines in promoting metastasis in GIST microenvironment.

METHODS

Expression levels of M2-TAM markers and CXCL2 in primary and metastatic tissues of GIST were analyzed by bioinformatics methods, and we analyzed the correlation between CXCL2 and M2-TAM markers. Immunofluorescence was applied to assay CXCL2 and M2-TAM marker protein (CD68 and CD206) expression in tumor tissues. Serum CXCL2 concentration in metastatic and non-metastatic patients was assayed by ELISA. The differentiation of THP-1 cells was tested by flow cytometry. Cell function test was utilized to analyze the viability, invasion and migration of GIST cells. Western blot was used to examine the expression of epithelial-mesenchymal transition (EMT)-related proteins. The mouse liver metastasis model was established, and the effects of CXCL2 and EMT-related genes on metastasis were confirmed by hematoxylin-eosin staining and immunohistochemistry experiments.

RESULTS

Bioinformatics analysis ascertained that M2-TAM marker proteins and chemokine CXCL2 were highly expressed in GIST metastatic tissues, and CXCL2 and TAM were co-located in tumor tissues. Results of in vitro cell function experiments displayed that CXCL2 secreted by M2-TAM promoted the invasion, migration and EMT of GIST tumor cells, and the anti-CXCL2 antibody could block the metastasis promoting effect of CXCL2. Additionally, the silencing of CXCR2 in GIST cells inhibited the metastasis promoting effect of CXCL2. Animal studies further confirmed that CXCL2 promoted liver metastasis of GIST in vivo.

CONCLUSION

This study preliminarily revealed the mechanism of M2-TAM promoting tumor metastasis by secreting CXCL2 in GIST tumor microenvironment, and proffered theoretical reference for the development of immunotherapy strategies targeting M2-TAM.

CircNRIP1: An emerging star in multiple cancers

Circular RNAs (circRNAs) are a new class of non-coding RNAs (ncRNAs) with a closed-loop structure that is highly stable and widely present in the eukaryotic cytoplasm. In recent years, circRNA has played a non-negligible role in the occurrence and development of a variety of diseases, which has attracted the research attention of many scholars. Circular RNA nuclear receptor interacting protein 1 (circNRIP1), a newly discovered circRNA, has been confirmed to be closely associated with cervical carcinoma (CC), colorectal cancer (CRC), esophageal squamous cell carcinoma (ESCC), gastric cancer (GC), nasopharyngeal carcinoma (NPC), non-small cell lung cancer (NSCLC), osteosarcoma (OS), ovarian cancer (OC) and papillary thyroid carcinoma (PTC). CircNRIP1 can regulate the activity of ERK1/2, PI3K/AKT, and AKT/mTOR signaling pathways. In this review, the author summarizes the biological functions and target molecular mechanisms in carcinogenesis, to point out the potential clinical values and applications of circNRIP1 in diagnosing and treating cancer.

CircNRIP1 Encapsulated by Bone Marrow Mesenchymal Stem Cell-Derived Extracellular Vesicles Aggravates Osteosarcoma by Modulating the miR-532-3p/AKT3/PI3K/AKT Axis

Emerging evidence indicates that extracellular vesicle (EV)-encapsulated circRNAs have the potential diagnostic and prognostic values for malignancies. However, the role of circNRIP1 in osteosarcoma remains unclear. We herein investigated the therapeutic potential of circNRIP1 delivered by bone marrow mesenchymal stem cell–derived EVs (BMSC-EVs) in osteosarcoma. The expression of circNRIP1 was examined in the clinical tissue samples of osteosarcoma patients, after which the downstream genes of circNRIP1 were bioinformatically predicted. Gain- and loss-of function assays were then performed in osteosarcoma cells with manipulation of circNRIP1 and miR-532-3p expression. EVs isolated from BMSCs were characterized and co-cultured with osteosarcoma cells to examine their effects on cell phenotypes, as reflected by CCK-8 and Transwell assays. Further, a mouse model of tumor xenografts was established for in vivo substantiation. circNRIP1 was upregulated in osteosarcoma tissues and cells. Overexpression of circNRIP1 promoted the proliferative, migratory, and invasive potential of osteosarcoma cells. Co-culture data showed that BMSC-EVs could transfer circNRIP1 into osteosarcoma cells where it competitively bound to miR-532-3p and weakened miR-532-3p’s binding ability to AKT3. By this mechanism, the PI3K/AKT signaling pathway was activated and the malignant characteristics of osteosarcoma cells were stimulated. In vivo experimental results unveiled that circNRIP1-overexpressing BMSC-EVs in nude mice resulted in enhanced tumor growth. In conclusion, the BMSC-EV-enclosed circNRIP1 revealed a new molecular mechanism in the pathogenesis of osteosarcoma, which might provide a novel therapeutic target for osteosarcoma.